Stiff Person Syndrome, Anti-GAD Syndrome 4.67/5 (12)

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Stiff person syndrome (SPS) = Autoimmune stiffness syndrome. ICD-10 M62

Stiff person

Stiff person syndrome with cramp in hands. Illustration Goodson B, 2010
CC BY 2.0.


Stiff person syndrome is a rare, neurological disease with increasing stiffness and cramps especially in the back muscles. Originally called "Stiff man syndrome". Some of the symptoms may initially be reminiscent of rheumatic disease


Stiff person syndrome is defined as one rare disease.


  • Most people get Stiff Person Syndrome at the age of 30-70.
  • Unable to stretch fingers can be early symptom
  • Pain that becomes chronic and increasing over time
  • The back muscles span, are rigid and have episodes with strong cramps
  • Very sensible (cramps) when exposed to unexpected physical activity and too loud sounds
  • The spine is developing abnormal posture with stretching (hyperlordosis)
  • Stomach muscles also become tight
  • Muscle rigidity causes the body to become stiff, first periodically over days-weeks, later more persistent
  • Pes equinus position
  • Problems with walking: "bizarre walk"
  • A variant of the disease mainly attacks the legs
  • About. 25% also has Type I Diabetes

Disease Causes

  • Paraneoplastic type
    • Associated with various cancerous diseases (neoplasms)
    • Different, unspecific Antibodies 
  • Idiopathic type (unknown cause of disease)
    • No typical antibody or cancer
    • Compose approximately 35% of cases

Medical investigations

By clinical examination can be demonstrated:

  • Hard and tight muscles
  • Visible simultaneous contractions of agonistic and antagonistic muscles
  • Stretch in the back and neck (hyperlordose)
  • The extremities become rigid in the stretched position (pointed foot)
  • Movements become stiff "like a tinn soldier"

Blood tests

  • Erythrocyte sedimentation rate (ESR), CRP, Creatine kinase (CK), ANA, ANCA are normal
  • GAD65 antibody
    • Material: serum volume: 0,5 ml
    • In Norway, analyzes (serum and spinal fluid) are done at Oslo University Hospital, Section for Medical Immunology, Ullevål Hospital and Haukeland Hospital.

Electromyography (EMG)

  • Simultaneous agonist + antagonist activation that responds to diazepam, otherwise normal outcome

MRI examination of the head and back

  • No special findings

Spinal Fluid

  • Antibody against GAD65 can be detected, otherwise normal


Obvious stiffness and rigidity in the back, neck and abs

  • Slow progression over time results in permanent reduced movement
  • Striking posture with stiffness in the back (hyperlordosis)
  • Cramps are triggered by unexpected motion, contact, sound or emotional imbalance
  • Normal sensibility
  • EMG with activated muscle activity and response to diazepam
  • Normal intellect
  • Antibody against GAD65 (glutamate decarboxylase 65kD isotype) of 60%

Incorrect diagnosis (similar conditions / differential diagnoses)


Medical prognosis

  • Variable disease progression, but often increasing symptoms over time
  • Possible correlation with cancer disease and type I diabetes must be followed up


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